Liquid fuel injection apparatus



Jan. 17, 1956 E. w. DOWNING LIQUID FUEL INJECTION APPARATUS 2Sheets-Sheet 1 Filed Aug. 5, 1952 A/ [1mm 1:: [:1

Jan. 17, 1956 .E. w. DOWNING 2,731,175

LIQUID FUEL INJECTION APPARATUS Filed Aug. 5, 1952 2 Sheets-Sheet 2United States Patent LIQUID FUEL INJECTION APPARATUS Eric WilliamDowning, Birmingham, England, assignor to Joseph Lucas (Industries)Limited, Birmingham, England Application August 5, 1952, Serial No.302,797

Claims priority, application Great Britain August 13, 1951 7 Claims.(Cl. 222-250) This invention relates to a liquid fuel metering device ofthe shuttle-type to which the fuel is supplied from a pump, and fromwhich the fuel is discharged intermittently to an internal combustionengine.

The range of movement of the shuttle of the metering device (and hencethe quantity of fuel discharged in each movement of the shuttle) isdetermined by a pair of end-stops, and to enable the said quantity to bevaried, one of the stops is made adjustable, either manually, orautomatically in response to, for example, variation of pressure in theair-intake manifold of the engine.

When the engine is cold, its fuel requirement is greater than that whichexists when the engine is hot, and the object of the present inventionis to enable both of these and other requirements to be met in asatisfactory manner.

The invention comprises a liquid fuel metering device of theshuttle-type in which the means for determining the position of theadjustable shuttle-stop, comprises a contoured and endwise movableabutment, means for effecting endwise movement of the abutment, a rockercooperating with the abutment, and means responsive to the air pressurein the engine air-intake manifold for imparting endwise movement to therocker relatively to the abutment.

In particular the invention comprises a stop-positioning means asspecified in the preceding paragraph, in which the abutment is adaptedto receive also a pivotal movement, and in which there are providedindependently operable means for imparting endwise and pivotal movementsto the abutment.

in the accompanying drawings:

Figures 1 and 2 are respectively sectional side and end elevations of anapparatus embodying the invention.

Figures 3, 4, 5 and 6 are fragmentary sectional plan views on the lines3.3, 4.4, 5.5, 6.6 in Figure 1.

Figure 7 is a fragmentary sectional plan on the line 7.7 in Figure 2.

Referring to the drawings, the fuel metering device is of known form,and consists of a slidable shuttle a contained in a rotary hollowcylindrical and ported valve 12, the latter being adapted to be drivenby the engine. The valve is contained in a ported barrel c secured inthe body part d. Fuel is supplied to the metering device by a feed pumpconnected by a pipe to the inlet 2, and is delivered to the enginecylinders through pipes connected to the outlets f. The shuttle a ismovable alternately in opposite directions by the pressure of liquidfuel admitted to the interior of the valve b. With the valve b in theposition shown in Figure 1, liquid fuel from the inlet e has access tothe interior of the valve at the right hand side of the shuttle, andmoves the shuttle to the left, this movement of the shuttle serving todischarge through the left hand outlet liquid fuel previously admittedto the interior of the valve at the left hand side of the shuttle.Rotation of the valve b then permits access of liquid-fuel from theinlet e to the in- 2,731,175 Patented Jan. 17, 1956 terior of the valveat the left hand side of the shuttle a, and the latter is moved therebyto the right for discharging through the right hand outlet liquid fuelpreviously admitted to the interior of the valve at the right hand sideof the shuttle. Rotation of the valve b permits the above sequence ofoperations to be successively repeated. One of the end-positions of theshuttle is determined by the fixed stop g. The other end-position isdetermined by the axially adjustable stop h which consists of a plungerextending through one end of the rotary valve b into the adjacentchambered portion of the body part.

The liquid fuel is usually supplied to the metering device at highpressure, and as the means employed for determining the position of thestop h must be sensitively responsive to relative small forces, it isdesirable that only an appropriate fraction of the fuel-pressure actingon the said stop shall be transmitted to the adjusting means. To meetthis requirement there is pivoted on a bracket i in the body part, alever j which at one end abuts against the stop and which at the otherend abuts against a plunger k contained in a cylinder m to which fuel isadmitted from the inlet e, so that the liquid pressure exerted on thelever by the stop It is partially counterbalanced by the liquid pressureexerted through the plunger k. On the lever j is mounted a roller nwhich co-operates with the stop adjusting means.

The stop adjusting means comprises an abutment o in the form of a barwhich is carried by and is endwise slidable on the bracket i. Theoperative edge of the abutment is contoured as shown, and comprises twostraight portions in parallel relationship, the junction between thesestraight portions being curved as indicated at p. Also the said bar ispivotally movable, its fulcrum being provided by a roller q carried bythe bracket i.

Between the abutment 0 and the lever j is arranged a rocker r which isshaped as shown and at one edge is in contact with the roller 11. At itsends the rocker carries a pair of rollers s, t. The roller s issupported on and is movable along a straight edge u on the bracket i,and the roller t is supported on the contoured edge of the abutment 0.It will be apparent that endwise movement of the rocker relatively tothe abutment, or endwise movement of the abutment relatively to therocker, will result in an angular movement of the rocker and acorresponding axial movement of the stop It.

In the example illustrated by the drawings, the rocker r is connected atone end by a link v to a piston w loaded by a spring x and slidable in acylinder y. One end of the cylinder is in communication with a passage 2in the body part (Figure 2) leading to a connection 3 for a pipeattached to the air-intake manifold of the engine. At atmosphericpressure, the piston occupies the position shown in the drawings, butwith appropriate reduction of air-pressure in the manifold the pistonwill be moved in opposition to the spring, causing the rocker to impartmovement to the lever and thence to the stop h. Moreover, endwisemovement of the abutment 0 will also effect movement of the rocker, andstop.

The drawings show the abutment in the position which it normallyoccupies when the engine is hot. In this condition variation of theposition of the stop 11 is determined by linear endwise movement of therocker (under the action of the piston w) along the bracket and theupper part of the abutment, and the movement imparted by the rocker tothe lever j and stop it is determined by the inclination of the edge ofthe rocker in contact with; the lever roller n.

When the engine is cold, and an increased amount of fuel is required bythe engine, the abutment is moved to its upper position. In thiscondition the roller t lies in contact with the lower part of theabutment, and in so moving the abutment, the rocker receives an angularmovement which allows the stop it to move outwardly to the requiredextent. While the abutment is in this condition, the amount of extrafuel supplied to the engine is also variable under the action of thepiston w.

For imparting endwise movement to the abutment 0, there is mounted onthe bracket i a slidabie rack 4 (Figure 2) from which extends a peg 5(Figure 5) which occupies a gap 6 (Figure l) in one side of theabutment. The rack is engaged by a toothed segment 3 which is operableby a lever 9. The lever is adapted to be actuated manually.Alternatively, or in addition, it may be operable by a thermostaticdevice of any convenient form. For example, there may be arranged in thecooling-water system of the engine an elastic extensible capsuleresponsive to the temperature of the water. The capsule is connected bylinkage or other means to the said lever 9, so that when the water iscold the abutment 0 is moved to its upper position, and when tr etemperature reaches a predetermined amount the capsule causes theabutment to be moved to its normal lower position shown in the drawings.

When starting a cold engine it may be desired to admit additional airtemporarily to the engine manifold, the intake throttle being wholly orpartially closed. To meet this requirement, the chambered portion of thebody part of the apparatus above described (to which air is admittedthrough an air inlet 593, Figure 2), is provided with a port if. leadingto a passage 12 which leads to a compartment 13. The latter is separatedfrom an adjacent compartment ld by a flexible diaphragm 15 which isloaded by a spring 16. The compartment 14 communicates with themanifold-connection 3 by way of a passage 17, and this passagecommunicates with the compartment 13 through an orifice 18 which isnormally closed by a valve 119, on the diaphragm. Further the spring 16is supported at one end by an abutment 29 on which bears a thrust rod21, the latter being held by an arm 22 extending from the rack 4. Whenthe engine is Working normally and the abutment o is in its lowerpoition, as shown in the drawings, the valve 319 is held on its seatingat the entrance to the orifice 18 by the spring 16. But when theabutment 0 is raised to its upper position, the arm 22 of the rack 4 isalso in its upper position, and in this condition the spring to exertslittle or no pressure on the diaphragm. Consequently the depression ofpressure in the air-intake manifold, which is communicated along thepassage 17 to the compartment 14, allows the atmospheric pressure in thecompartment 13 to raise the valve 19 or? its seating and permits air topass from the said compartment to the pipe connection 3 and thence tothe intake manifold. On return of the abutment 0 to its normal positionthe rack-arm 22 again brings the spring 16 into action and so causes thevalve 33 to be returned to and held in its closed position.

To enable the position of the stop It to be adjusted in response to acondition other than the condition existing in the intake manifold, suchas a change of atmospheric air pressure, or the speed of the engine, theangular freedom of the abutment is utilised. In the arrangement shown inthe drawings, there is supported on a tail piece 24 depending from thebracket i, a laterally slidable wedge piece 25 against which theabutment o bears when in its normal power position. On movement of thewedge piece, the abutment 0 is given an angular movement on its fulcrumq, so causing the rocker r by its action on the lever j to vary theposition of the stop It. In the example shown the wedge piece isoperable by an evacuated elastic bellows 26 contained in a chamber 27which is open to the atmosphere. One end of the capsule is fixed and thewedge piece is attached to the free end of the capsule. Variation ofatmospheric air pressure causes variation of the length of the capsuleand consequent movement of the wedge, this resulting in an angularmovement of the abutment. Preferably the chamber 27 is isolated from thechamber containing the stop-positioning means by a flexible diaphragm28.

Instead of arranging the wedge piece to be movable with a change ofatmospheric pressure, a centrifugal governor responsive to the speed ofthe engine may be used for actuating the wedge. Alternatively any otherdevice responsive to a variable condition associated with or atfectingthe normal action of the engine and requiring corresponding regulationof the rate of fuel supply, may be used.

By this invention, adjustment of the position of the movable stop of thefuel metering device, to meet different engine-working conditions can beeffected in a convenient manner.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

l. A shuttle-type liquid fuel metering device comprising in combinationa hollow and ported cylindrical rotary valve, a shuttle slidable in saidvalve, an inlet for supplying liquid fuel under pressure to the interiorof said valve at opposite sides of said shuttle alternately, outletsthrough each of which fuel from the interior of said valve at one sideof said shuttle is dischargeable by said shuttle under the pressure ofliquid fuel admitted to the interior of said valve at the opposite sideof said shuttle, a pair of stops for limiting the extent of the slidingmovement of said shuttle, one of said stops being adjustable, acontoured and endwise movable abutment, a rocker cooperating with saidabutment for determining the position of said adjustable stop, means foreffecting endwise movement of said abutment to cause said rocker to varythe position of said adjustable stop, and additional means responsive toair pressure for effecting endwise movement of said rocker relatively tosaid abutment to vary the position of said adjustable stop independentlyof endwise movement of said abutment.

2. A shuttle-type liquid fuel metering device according to claim 1, inwhich said contoured and endwise movable abutment is also capable ofpivotal movement for causing said rocker to vary the position of saidadjustable stop independently of endwise movements of said abutment androcker, and in which means are provided for cooperating with saidabutment to effect the said pivotal movement thereof.

3. A shuttle-type liquid tuel metering device according to claim 1, inwhich said abutment is supported by a fixed part, and in which saidrocker is provided at its opposite ends with a pair of rollers, thelatter being arranged to bear respectively against said abutment andfixed part so that rocking movement can be imparted to said rocker byendwise relative movements of said rocker and abutment.

4. A shuttle-type metering device according to claim 1 and having alever through the medium of which the said adjustable stop is movable bysaid rocker, and means responsive to the pressure of liquid fuelsupplied to said ported cylindrical rotary valve for exerting on saidlever a force opposing that transmissible to said lever through themedium of said adjustable stop, so that only a fraction of the fuelpressure acting on said adjustable stop is transmissible to said rocker.

5. A shuttle-type metering device according to claim 1, in which themeans for effecting endwise movement of said abutment comprise incombination a slidable rack operatively connected to said abutment, arotary toothed member engaging said rack, and means for actuating saidrotary toothed member to impart movement through said rack to saidabutment.

6. A shuttle-type liquid fuel metering device according to claim 1, inwhich said contoured and endwise movable abutment is also capable ofpivotal movement for causing said rocket to vary the position of saidadjustable stop independently of endwise movements of said abutment androcker, and in which a laterally slidable wedge piece having operatingmeans associated therewith is provided for co-operating with saidabutment to effect the said pivotal movement thereof.

7. A shuttle-type liquid fuel metering device according to claim 1 andhaving in combination therewith a valve responsive to air pressure, anda spring through the medium of which said valve is loaded under thecontrol of the means for effecting endwise movement of said abutment.

References Cited in the file of this patent UNITED STATES PATENTSSummers Apr. 28, 1931 Starr Mar. 8, 1938 Morgenroth Aug. 20, 1946Morgenroth Aug. 20, 1946

